^Many clients claim to support this, but just UPnP calls for opening a TCP port is not effective and disabled by factory default in most new hardware. "UDP NAT Traversal" is the proper working solution, supported by just a few.

^DHT permits use of trackerless torrents (with supporting clients) to resume normal torrents when their tracker is down. However, some trackers that register their users for keeping tabs on fair usage (such as a ratio of bytes downloaded to uploaded) may not reliably measure and update usage for users employing DHT.

^ abcTracker included with Linux binaries and with source, but not with Windows binary.

^It's UDP based, an experimental feature and only supported by other Azureus based clients.

^ abcHas its own DHT, a mainline-DHT compatible implementation is available as plugin.

^µTorrent's DHT implementation is the same as Mainline and BitComet's, but unfortunately this is incompatible with Azureus's implementation.

^Since Shareaza v2.6.0.0, Shareaza includes Mainline DHT support. Also, Shareaza can use the Gnutella2 network to find other Gnutella2 clients sharing the same torrent. This also includes clients who do not actively seed the torrent in question anymore, as long as file hashes (such as sha1 for example) are known.

^Many clients claim to support this, but just UPnP calls for opening a TCP port is not effective and disabled by factory default in most new hardware. "UDP NAT Traversal" is the proper working solution, supported by just a few.

^DHT permits use of trackerless torrents (with supporting clients) to resume normal torrents when their tracker is down. However, some trackers that register their users for keeping tabs on fair usage (such as a ratio of bytes downloaded to uploaded) may not reliably measure and update usage for users employing DHT.

^Reduces disk usage, file fragmentation (in case it is not preallocated) and latencies due to larger written blocks and cached data for hash checking finished pieces.